1. Field of the Invention
The present invention relates generally to the generation of update packages by a generator that can be used to update firmware/software components in mobile handsets.
2. Related Art
Electronic devices, such as mobile phones and personal digital assistants (PDA's), often contain firmware and application software that are either provided by the manufacturers of the electronic devices, by telecommunication carriers, or by third parties. These firmware and application software often contain software bugs. New versions of the firmware and software are periodically released to fix the bugs or to introduce new features, or both.
There is a problem with generating update packages in an efficient mode when at least a portion of the content in a mobile phone image is compressed, or encrypted, or both. There is a problem in minimizing the size of an update package that contains a difference information for a code transition between an old version to a new version.
A common problem in the differential compression of executable files is the pointer mismatch due to code relocation. When a block of code is moved from a memory region to another, all pointers to that region will change accordingly. If in the old version a pointer points to an address A and in the new version of the same code, the same pointer points to B, it is likely that other pointers to A will be changed in the new version into pointers to B. Incorporating such issues into a solution is not easy. In addition, automating the generation of update packages when code changes dramatically between an old version and a newer version is still an art form and prone to errors, and therefore needs tweaking.
Efficient encoding of references that are relocated by the same offset in the new software version is necessary, but is a complex problem. One related question is when such encoding needs to be conducted. If a block of code contains mismatches, one problem is to decide if mismatches are individually encoded or not. These and other problems are typically encountered during the generation of an update package.